There's any number of DIY techniques to grow vegetables with many nowadays focusing on garden design. While design is important, I think what is often neglected is what you make your garden with.

I'm beginning to think that my answer is straightforward. The stuff from which I make my vegetable garden is made up of:

earthworms

grass clippings

car tires

As far as chicken and egg theory goes, I'm not sure what is supposed to come first. I began with a worm farm made out of car tires stacked one upon the other. I then tipped the contents of my farm -- complete with "Tiger" earthworms onto what was my vegetable garden.

I had always covered the garden with a mulch of grass clippings and used the standard newspaper underlay but what always frustrated me was the way the beds I planted were so cumbersome to administer. I'd build up walls from old bits of concrete and found bricks and planted my veges within the perimeter. But the size of these beds were about that of the double bed I sleep on.

Car Tires turned inside out

Gardening with Circles

Since I used tires to build my worm farm, I did some homework and noted that you can use old car tires to make garden "beds". While the standard approach with old tires is to simply fill their middle with soil and plant, I thought that was wasteful of space as the tire itself curls in and lips. So I trimmed the tires and turned them inside out.

When you prepare them like this you get a straight vertical circular wall 20 centimetres (or 8 inches) high . This rubber rim is easy to embed in the soil so that it is anchored, sticking up from it as much as you prefer. I wanted to sink the tires so that their sides didn't get to hot, I was keen to mulch them on their exterior rim while I filled their centre with soil, compost and a blanket layer of grass clippings. It's like layering a birthday cake where the mulching layer is the thick layer of icing on top -- right up to the rim.

Since with tires cut like this you are working with circles, there are many patterns you can use to create your garden. Generally a garden "bed" is two tires wide as that's the limit of my reach between paths. However while you have space within circles you also have the space between circles. And since the walls are so thin, despite your circle pattern, you are still making great use of available space such that your space loss quotient is hardly significant compared to creating garden beds in rectangular shapes.

So if we consider the sketch at right you see that instead of one garden bed six are available plus two inner spaces . The knack with tire circle gardening is that you treat the space within each circle -- within each tire -- as its own micro garden. By that I mean each circlular micro garden is treated as a separate and individual growing unit such that it has its own identity determined by its location, relationship to other circles, its soil and biomass contents; micro-organism activity and soforth.
Furthermore, since you work in complex patterns made up of seemingly independent units, there is more compulsion to grow a mix of plantspecies within each circle as planting in regimented monocultural rows isn't an option. It's like treating each bed into its own geodesic dome.

Worm Farming First and Foremost

But here's the trick: when you divide up you garden like this and have vermiculture in mind that's how you treat the circles -- as worm beds; and raising earthworms in these beds is what you try to do. You're a worm farmer first and foremost. What that means is that each bed's value is determined by the richness of its soil life measured not only in soil texture but overwhelmingly by the amount of earthworm activity you can sponsor within each circle.

The worms aren't (Vermiculture)Tigers of course -- at least there's few Tigers active and alive in this soil -- but you act as a benevolent landlord for the earthworms that take up residence.

So when creating a circular bed, I turn over the soil and scrpe it into a central mound so I can sink the cut tire into the soil (usually about 10-15cm deep) around it, then spade the scrapings back, add some new soil, compost (created in my compost bins made from tires) and a topping of grass clippings at least 3 inches/ 7 cm thick and layered on unevenly so that there's a lot of topography to the surface of the bed.

I measure these beds' 'health' by digging with my fingers, pulling back the compost and turning over the soil to feel the moisture level but most of all if I cannot locate an earthworm or two I'm thinking I need to put the bed on an enriched diet of customized attention.

I haven't given each bed pet names -- not yet anyway!-- but the relationship is indeed personal.

You'll note that such personalized attention presumes that I will water regularly as almost a daily chore and unlike the habits preached by the gardening gurus,I work to ensure that that layer of compost and soil within the tire's full depth is kept moist and my soil activity is kept in adequate hydration. It's like treating it as a pot plant.

Watering the tire circles is always light and of short duration. After a time there's enough stuff happening within the soil/mulch that a lot of the moisture is retained within the tire's soil volume and you don't have to drown the bed at all. The size of circle also approximates the diameter of a flower jet on a gardening hose so you water one bed at a time with very little or no spray falling outside the circle.

However, because you are earthworm farming you must attend to all beds whether they are planted or not because earthworms and soil activity don't take a vacation .

Walking Circles

My plot also includes fruit trees -- a 20 year old mango tree among them. Because of ever present tree roots I was keen to raise the garden beds up so that I separated as much as I could tree activity from the growing of annuals. While this was my intention, this conceptual separation also meant that I could treat each circular bed as something I could move around, like an ice hockey put.

By lifting up the tire circle, which peels away like a cake sponge mould, I can walk the bed to another place by first instaling the tire and lifting the soil with a flat spade from the original location and spooning it into the new address. So I do indeed treat the cicles like pot plants -- broad bottomless pots.